Cathode ray tubes, of the types employed in color television and allied display applications, are often provided with a magnetic shielding arrangement to protect the tube from numerous stray voltages, currents and magnetic fields, including the earth's magnetic field, which tend to adversely affect the desired performance of the tube. While shielding means externally surrounding the tube have been extensively utilized, it has been found that magnetic shields internally disposed in a spaced manner within the tube envelope provide better shielding effects with a resultant marked improvement in the tube performance. Such internal shielding members are usually formed of a substantially continuous bowl-like sidewall having a substantially full frontal opening and a smaller rear opening defined by the terminal perimeter of a continuous ledge instanding from a transition region between the ledge and the sidewall.
It has been conventional practice to attach a flexible electrical contactor to the rear portion of the shielding member to bridge across and make electrical connection with the conductive coating disposed on the interior surface of the funnel portion of the tube. One means of contactor attachment to the shielding member was by welding which tended to erratically produce splatter. The resultant loose particles therefrom are detrimental to tube operation, such as by blocking apertures in the shadow mask or causing shorts and high voltage arcing.
An improvement in the state of the art was disclosed in U.S. Pat. No. 4,310,779, assigned to the assignee of the present invention, wherein the contactor has a clip-on attachment element which is facilely affixed to a fluting formed in the rear ledge of the shielding member. While this clip-on contactor represents a marked improvement, there have been occasions, such as upon a severe impact shock, when the contactor was shifted to an undesired position. Accordingly, the present invention relates to combination means for preventing shifting of the contactor once it is attached to the shielding member.